Medical treatment options for endometriosis remain limited, and there is a significant unmet medical need for non-surgical treatments. Population pharmacokinetics of elagolix (gonadotropin-releasing hormone (GnRH) receptor antagonist) have not been previously reported. Therefore, in this study, the author revealed that elagolix pharmacokinetics were similar between healthy women and women with endometriosis.

Elagolix is a novel, non-peptide, competitive gonadotropin-releasing hormone (GnRH) receptor antagonist, and orally active used to manage endometriosis and related pain along with heavy menstrual bleeding due to uterine fibroids.  The Elagolix pharmacokinetics has been well-identified in phase I studies, but Elagolix population pharmacokinetics have not been studied earlier. This study explains the Elagolix population pharmacokinetics and factors affecting Elagolix pharmacokinetic parameters by developing a robust model.

Nine studies selected for analysis; four phase III studies in premenopausal females with endometriosis and five phase I studies in healthy, premenopausal females.

A two-compartment model with absorption lag time well-described the Elagolix population pharmacokinetics. Only organic anion transporting polypeptide (OATP) 1B1 genotype status out of the 15 covariates examined for influence on Elagolix apparent clearance (CL/F) and/or volume of distribution found to be statistically significant, but not clinically relevant, the effect on elagolix CL/F.

Elagolix pharmacokinetics were not influenced by patient demographics and were related within healthy females and females with endometriosis.